This might give you a taste. The letters ending each line are just for linking the songs to the books.


                           Index of Folk Songs

Penguin Book of American Folk Songs………………………………….AFS
Book of British Ballads (RP)………………………………….………….BBB
A Ballad History of England (RP)……………….…………….…………BHE
Boxing the Compass (RP)………………………………………………...Box
Ballads, Songs and Pipe-Tunes II………………………………………...BSP
Clancy Brothers Song Book……………………………………….……..CBS
Collected Folk-Songs Vol.1………………………………………………CF1
The Constant Lovers……………………………………………………...Con
The Copper Family Song Book…………………………………………..Cop
The Crystal Spring…………………………………………………………CS
Book of English Country Songs (RP)……………………….……………ECS
Eighty English Folksongs……………………………...…………………EEF
The English Folksinger…………………………………….......…………EFS
English Traditional Songs and Carols…………………………………….ETS
Folk Songs of England, Ireland, Scotland and Wales…………………….FGB
Folk Songs Today 1 and 5……………………………………………....FS1,5
Folk Songs of Lancashire…………………………………………………FSL
Folk Song in England……………………………………………………..FSE
Folk Songs from Somerset………………………………………….…….FSS
Folk Songs of the West Country………………...……………………….FSW
Great Australian Folk Songs……………………………………………..GAF
Garland of Country Songs (RP)…………………………………………...Gar
Songscapes (GM).………………………………………………………...GM
The Jolly Herring…………………………………………………………Her
The Joan Baez Songbook…………………………………………………JBS
Traditional Tunes………………………………………………………….Kid
Marrow Bones………………………………………………………….…Mar
100 Folk Songs and New Songs…………………………………………..100
Penguin Australian Song Book……………………………………………Pas
Penguin Book of English Folk Songs………………………………….….Pen
Poverty Knock (RP)..……………………………………………………...PK
The Painful Plough (RP)……………………………………………………PP
The Rambling Soldier (RP)……………………………………………….Ram
The Rigs of the Fair (RP)………………………………….………………..RF
Room for Company (RP)………………………………………………….RfC
Folk Songs collected by RVW (RP).……………………………………RVW
The Song and the Story……………………………………………………SaS
Strike the Bell (RP)…………………………………………………………SB
Sea Songs and Shanties…………………………………………...……….Sea
A Song for Every Season………………………………………………….SES
Sing High Sing Low………………………………………….…………….Sin
Seeds of Love, The…………………………………….…………………SoL
Songs and Music of the Redcoats………………………………………..SMR
The Sound of History……………………………………………………..SoH
Songs of the Midlands…………………………………………………....SoM
Songs for Today……………………………………………….…………..Son
A Swag of Songs………………………………………………….……….SoS
Songs and Marches of the Roundheads and Cavaliers……………………SRC
Sussex Songs……………………………………………………………….SS
Shanties and Sailors’ Songs……………………………………………….SSS
A Touch on the Times………………………………………………….....ToT
Tunes to Poems and Songs, MW-R………………………………………TPS
The Singing Island………………………………………………………...TSI
Windmills (AB)..…………………………………………………………Win

Any specific queries about the books can, hopefully, be answered.